1. Field of the Invention
The present invention relates a golf club.
2. Description of the Related Art
One of the related art of a golf club of the invention is illustrated for example in FIG. 1 of Japanese Un-Examined patent publication number 5-285238, disclosing a golf club head in which a face member is press-fitted into a recess portion formed in a face corresponding portion of a head body, while the head body and the face member are made of different materials from each other so that a position of the center of gravity in the head can be adjusted. However, as two different materials are used in the prior art, one for a head body and the other for a face member respectively, there has thus far been a limit to the adjustment of the position of the center of gravity.
Whereas, it is well known that lowering the position of the center of gravity in a head is particularly advantageous to certain golfers who swing golf clubs at relatively low head speed. For lowering the position of the center of gravity, it is effective to combine a plurality of metals each having different specific gravity as above mentioned. Light metals such as titanium, aluminum or the like may be used mainly for a head body, while heavy metals may be used for a sole portion as a balance weight. Heretofore have been used copper alloy, stainless steel, tungsten alloy or the like for such balance weight. Among them, tungsten alloy has a larger specific gravity so that the position of the center of gravity of a head can be lowered effectively by employing the same.
However, tungsten alloy has a poor extensibility as it is generally produced through a powder sintering method. Accordingly, when joining tungsten alloy to other materials, caulking is not available unlike to copper alloy or the like, so that screws and pins are generally used to join tungsten alloy to other materials, as taught, for example, in Japanese Un-Examined patent publication number 10-211304. In that case, however, exposure of screws and pins to the external is not desirable in terms of appearance.
When attaching a balance weight, it should naturally be attached to the vicinity of a sole if lowered center of gravity is preferred. According to a conventional construction, however, a balance weight is attached to a recess that is formed from outside an iron head. For example, in golf club illustrated in FIG. 1 of Japanese Registered patent publication number 2838876, a balance weight is fixed to a recess formed on a rear face of a head body. Such conventional structure causes no problem in the case that a balance weight is small. However, if a lower position of the center of gravity is required and thus a larger balance weight eventually has to be attached, there is the likelihood that the joint strength may be decreased, depending upon an attachment position and a joint area, which is not desirable from a standpoint of a degree of freedom for design.
To eliminate the above-mentioned problems, it is, therefore, an object of the present invention to provide a golf club comprising a head with a lowered center of gravity as well as a good external appearance.
To attain such objects, there is provided, according to a first aspect of the present invention, there is provided a golf club with a face on a front and a shaft attachment portion connected with a shaft, comprising: a head body including said shaft attachment portion and a recess portion formed in a portion corresponding to said face; a face member provided in said recess portion; either a recess portion or a through-hole formed in a sole portion of said head body in a longitudinal direction; and a balance weight provided in said recess portion.
According to the construction of the first aspect, not only the volume of the balance weight but also the weight thereof can be increased.
According to a second aspect of the present invention, there is provided a golf club according to the first aspect, wherein a front portion of the balance weight is abutted against a rear face of said face member.
According to the construction of the second aspect, the balance weight can be fixedly attached to the face member by anchoring the former with the latter.
According to a third aspect of the present invention, there is provided a golf club according to the first aspect, wherein said balance weight makes up at least 35% of the total weight of said head.
According to the construction of the third aspect, the position of the center of gravity can be lowered effectively.